This paper is the second in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C and the certification of reference preparations. Other parts deal with: Part 1. The Concept of Reference Procedures for the Measurement of Catalytic Activity Concentrations of Enzymes; Part 3. Reference Procedure for the Measurement of Catalytic Concentration of Lactate Dehydrogenase; Part 4. Reference Procedure for the Measurement of Catalytic Concentration of Alanine Aminotransferase; Part 5. Reference Procedure for the Measurement of Catalytic Concentration of Aspartate Aminotransferase; Part 6. Reference Procedure for the Measurement of Catalytic Concentration of gamma-Glutamyltransferase; Part 7. Certification of Four Reference Materials for the Determination of Enzymatic Activity of gamma-Glutamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37 degrees C. A document describing the determination of preliminary reference values is also in preparation. The pro- described 30 degrees C IFCC reference method (1). Differences are tabulated and commented on in Appendix 3.

This paper is the third in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C and the certification of reference preparations. Other parts deal with: Part 1. The Concept of Reference Procedures for the Measurement of Catalytic Activity Concentrations of Enzymes; Part 2. Reference Procedure for the Measurement of Catalytic Concentration of Creatine Kinase; Part 4. Reference Procedure for the Measurement of Catalytic Concentration of Alanine Aminotransferase; Part 5. Reference Procedure for the Measurement of Catalytic Concentration of Aspartate Aminotransferase; Part 6. Reference Procedure for the Measurement of Catalytic Concentration of gamma-Glutamyltransferase; Part 7. Certification of Four Reference Materials tamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37 degrees C. A document describing the determination of preliminary upper reference limits is also in preparation. The procedure described here is deduced from the previously described 30 degrees C IFCC reference method (1). Differences are tabulated and commented on in Appendix 1.

This paper is the first in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C and with the certification of reference preparations. Other parts deal with: Part 2. Reference Procedure for the Measurement of Catalytic Concentration of Creatine Kinase; Part 3. Reference Procedure for the Measurement of Catalytic Concentration of Lactate Dehydrogenase; Part 4. Reference Procedure for the Measurement of Catalytic Concentration of Alanine Aminotransferase; Part 5. Reference Procedure for the Measurement of Catalytic Concentration of Aspartate Aminotransferase; Part 6. Reference Procedure for the Measurement of Catalytic fication of Four Reference Materials for the Determination of Enzymatic Activity of y-Glutamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37 degrees C. A document describing the determination of preliminary reference values is also in preparation.

In response to proposals of scientific associations the German Medical Association recommended the use of international standard procedures for the determination of enzymes and a change of the measurement temperature to 378C in 1992. According to the recommendations, reference intervals for the new reference procedures should have been published by 1995. After a transition period, which had been extended several times, the clinical chemistry laboratories finally had to follow the recommendations and to use the new IFCC reference procedures as of April 1, 2003. However, reference intervals evaluated in a multicentre study have not been published until now. There is only one German study on preliminary upper reference limits of five enzymes in serum of hospitalized subjects using the new IFCC reference procedures. Since no multicentre study is intended in the near future, an expert working group of DGKL and VDGH recommended the use of preliminary reference intervals on enzymes in serum until final values have been determined. The interim values result from experiences of the past 3 years, from previous studies in different countries using comparable methodologies, or were derived from reference intervals obtained at 258C and converted by method and temperature conversion factors. ZusammenfassungAuf Vorschlag wissenschaftlicher Fachgesellschaften hat die Bundesä rztekammer 1992 die Einfü hrung internationaler Standardmethoden zur Bestimmung von Enzymaktivitä ten und damit auch die Umstellung der Messtemperatur von 258C auf 378C beschlossen. Referenzintervalle fü r die neuen Enzymmethoden sollten bis Ende 1995 verö ffentlicht werden. Nach einer mehrmalig verlä ngerten Ü bergangsphase bestand fü r die Laboratorien die Verpflichtung die neuen IFCC-Methoden ab 1.4. 2003 anzuwenden. Referenzbereiche, ermittelt in einer multizentrischen Studie, wurden nicht verö ffentlicht. Bisher liegt nur eine publizierte deutsche Studie vor, bei der lediglich an Krankenhauspatienten fü r fü nf Enzyme die oberen Referenzbereichsgrenzen bei 378C adaptiert an die IFCC-Methoden vergleichend zu den frü heren 258C-Methoden gemessen wurden. Da eine multizentrische deutsche Referenzwertstudie bisher nicht geplant ist, empfiehlt eine Arbeitsgruppe aus Experten der DGKL und des VDGH vorlä ufige obere Referenzbereichsgrenzen, die bis zur Erhebung definitiver Werte in einer multizentrischen Studie Gü ltigkeit haben sollen. Die vorlä ufigen oberen Referenzbereichsgrenzen beruhen auf einer 3-jä hrigen Erfahrung, wurden an frü here internationale Publikationen adaptiert oder von den 258C-Methoden abgeleitet.Schlü sselwö rter: Enzyme; IFCC-Methoden; Referenzbereiche.

This paper is the eighth in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C and the certification of reference preparations. Other parts deal with: Part 1. The concept of reference procedures for the measurement of catalytic activity concentrations of enzymes; Part 2. Reference procedure for the measurement of catalytic concentration of creatine kinase; Part 3. Reference procedure for the measurement of catalytic concentration of lactate dehydrogenase; Part 4. Reference procedure for the measurement of catalytic concentration of alanine aminotransferase Part 5. Reference procedure for the measurement of catalytic concentration of aspartate aminotransferase Part 6. Reference procedure for the measurement of catalytic concentration of gamma-glutamyltransferase; Part 7. Certification of four reference materials for the determination of enzymatic activity of gamma-glutamyltransferase, lactate dehydrogenase, alanine aminotransferase and creatine kinase at 37 degrees C. The procedure described here is deduced from the previously described 30 degrees C IFCC reference method. Differences are tabulated and commented on.